Since the majority of food waste in high-income countries occurs at the consumption stage and given the clear trend towards out-of-home food consumption, it is important to understand the factors that lead to food waste in the hospitality sector. The present study uses a behavioral structural equation model to test the drivers of consumers’ leftover behavior in an out-of-home setting. Based on the Theory of Planned Behavior, we additionally consider “personal norms” and the situational “taste perception” of food as determinants. Our results in a company canteen demonstrate that personal norms and attitudes greatly determine consumers’ intention to prevent leftovers, whereas subjective norms and perceived behavioral control appear less relevant. Stated leftover behavior depends on both behavioral intention and the situational taste perception of food. We show that in order to understand individual food leftover behavior in an out-of-home setting, determinants from behavioral theories should be complemented by situational variables.